Field of the Invention
The present invention relates to a photoelectric converter which is used for autofocusing by a phase-difference detection method.
Description of the Related Art
Japanese Patent Laid-open No. 2013-54333 discloses a focus detection sensor which has a first accumulation mode and a second accumulation mode. In the first accumulation mode, the focus detection sensor integrates charges generated by a photoelectric conversion element in a pixel without transferring the charges to a memory unit until completion of a charge accumulation period, and it transfers the charges after the completion of the charge accumulation period. In the second accumulation mode, the focus detection sensor transfers the charges generated by the photoelectric conversion element during the charge accumulation period to the memory unit, and it monitors an integrated value of the charges in the memory unit.
However, when the focus detection sensor disclosed in Japanese Patent Laid-open No. 2013-54333 is used with a high dynamic range in the second accumulation mode, the linearity is deteriorated.